That's good to know. I should probably put less faith in this particular test as I haven't calibrated it. The Salifert test I used to have read spot on with a triton test years ago, and also matched a Red Sea test I had at the time. I liked it in that it was much faster than the RS test. One day out of nowhere the Salifert test (which was a year or two old at that point) started under-reading by > 50 PPM (tested multiple times) when compared to both the RS test and what I expected the tank to be at (I was testing 2x monthly and dosing at that point). Will probably get one when the RS test runs out, but the sudden change bothers me a bit.I have the Salifert K Test kit. It reads about 20-30 lower than Triton.

